Billboard optic



FIG. 1 is a perspective view of the billboard optic;

FIG. 2 is a front view of the billboard optic;

FIG. 3 is a back view of the billboard optic;

FIG. 4 is a left side view of the billboard optic;

FIG. 5 is a top view of the billboard optic; and,

FIG. 6 is a bottom view of the billboard optic.

The broken line disclosure in the views represents portion of the optic which form no part of the claimed design. 

CLAIM The ornamental design for a billboard optic, as shown and described. 